Question

The graph below shows the position of a toy over time, measured using photogates.

At which of the labeled points is the car's velocity at a single moment lowest?

A. Point A
B. Point B
C. Point C.
D. Point D.

Answer 1

c

Step-by-step explanation:

Answer 2

Point C.

Explanation

`\textbf{Velocity} = \frac{\text{Change in }\textbf{displacement}}{\text{Change in Time}} = \frac{\Delta {\bf x}}{\Delta t}`.

`(\Delta x)/(\Delta t)` is the same as the gradient of the tangent to the position-times graph at the point in question.

Draw a tangent line to the curve at each point. Measure the gradient of each tangent line. The gradient of the tangent line to the curve is smallest at point C among all four points. Therefore, the car's velocity is smallest at point C.